I first experienced this product with my dog. (they make a dog version) It helped her tremendously with her limping due to arthritis. Literally hasn't limped in over 6 months since taking. So I bought this for my husband whose knees bother him frequently. Hasn't been on it long, but he has noticed that he can lift more weight at the gym without knee pain.

My husband is an endurance cyclist and he says that when he adds this to his drink mix he is able to "buffer lactic acid" much more efficiently. In other words, it takes longer for his legs to start burning.